Fertile Window
Calculator for Women
Calculate your fertile window and identify peak fertility days for conception planning. This free calculator estimates your 6-day fertility window based on cycle data.
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How This Fertile Window Works
The fertile window spans approximately 6 days: the 5 days before ovulation plus ovulation day itself. This calculator estimates ovulation as occurring 14 days before your next period and calculates the surrounding fertile days. Peak fertility occurs in the 2-3 days leading up to and including ovulation.
When Should You Use This Tool
Use this calculator when trying to conceive to identify optimal timing. The fertile window represents the days when pregnancy is possible, with peak fertility offering the highest conception chances. Track multiple cycles for more accurate predictions.
Is This Tool Accurate and Safe
This calculator provides estimates based on average biological patterns. Actual ovulation timing varies between cycles and individuals. For conception planning, consider combining this with ovulation predictor kits or basal body temperature tracking. All data remains private in your browser.
Frequently Asked Questions
How long is the fertile window for women?
The fertile window typically spans 6 days: 5 days before ovulation when sperm can survive, plus ovulation day. Peak fertility is the 2-3 days immediately before ovulation.
When is a woman most likely to get pregnant?
The highest pregnancy probability occurs 1-2 days before ovulation. Sperm can survive up to 5 days in fertile cervical mucus, while eggs remain viable for only 12-24 hours after release.
Can I get pregnant outside my fertile window?
Pregnancy is highly unlikely outside the fertile window. However, if your cycles are irregular, ovulation timing may vary, creating uncertainty about your actual fertile days.
How accurate is fertile window calculation?
Calendar-based calculations provide estimates. Accuracy improves with consistent cycle lengths. Women with irregular cycles should use additional tracking methods like ovulation tests.